1. Technical Field
The present disclosure relates generally to a wireless device that receives radio frequency (RF) energy from multiple RF transmission sources. More specifically, the present disclosure relates to an radio frequency identification (RFID) tag that, in addition to receiving RF energy from a corresponding RFID reader for RFID data communications, also receives RF energy from another wireless device, such as a cellular telephone, to power a component (e.g., a sensor) in the tag.
2. Background Information
Radio frequency identification (RFID) communications typically occur between an RFID-enabled reader and an RFID-enabled tag. The reader and the tag each comprise transceivers that wirelessly communicate with each other. In some implementations, the tag is passive. A passive tag does not have its own source of power and is thus temporarily powered by radio frequency (RF) energy transmitted by a near-by reader. The effective communication range for a reader and tag is typically fairly limited. In the absence of a reader (and its transmitted RF energy), a passive tag is generally unable to be powered on and perform useful work.